What is the initial workup for a patient presenting with hematuria (blood in urine)?

Initial Workup for Hematuria

The initial workup for hematuria should include urinalysis with microscopic examination, laboratory tests to assess renal function, and appropriate imaging based on risk stratification, followed by cystoscopy in high-risk patients or those with persistent unexplained hematuria. 1

Classification and Initial Assessment

• Hematuria is classified as either gross (visible) or microscopic (detected on urinalysis) 1, 2
• Microscopic hematuria is defined as ≥3 red blood cells per high-power field on microscopic evaluation of urinary sediment from at least two of three properly collected urinalysis specimens 1
• Dipstick positive results should always be confirmed with microscopic examination due to limited specificity (65-99%) 1
• Initial assessment should rule out benign causes including infection, vigorous exercise, menstruation, sexual activity, trauma, and certain medications 1, 3

Risk Stratification

• Gross hematuria carries a high risk of malignancy (30-40%) and requires urgent urologic referral regardless of other factors 4, 2
• Risk factors for significant urologic disease include:
  • Age >40 years 1, 3
  • Smoking history 3
  • Male gender 1
  • Occupational exposure to chemicals or dyes 3
  • History of urologic disease or pelvic irradiation 1
  • Chronic urinary tract infections 1
  • Analgesic abuse 3

Laboratory Evaluation

• Complete urinalysis with microscopic examination should assess:
  • Number of red blood cells per high-power field 1
  • Presence of dysmorphic red blood cells or red cell casts (suggesting glomerular source) 1, 3
  • Presence and degree of proteinuria 1
  • Evidence of urinary tract infection 1
• Serum creatinine should be measured to assess renal function 1, 3
• Urine culture should be obtained if infection is suspected 3
• Urine cytology is recommended for patients with risk factors for transitional cell carcinoma 1

Determining the Source of Hematuria

• Glomerular source indicators:
  • Significant proteinuria (>500 mg/24 hours) 3
  • Dysmorphic red blood cells 1, 3
  • Red cell casts 1, 3
  • Elevated serum creatinine 1
• Non-glomerular (urologic) source indicators:
  • Normal-shaped RBCs 3
  • Minimal or no proteinuria 3
  • Normal serum creatinine 3

Imaging Recommendations

• For patients with gross hematuria or microscopic hematuria with risk factors:
  • CT urography is the preferred imaging modality for comprehensive evaluation of the upper urinary tract 1, 4
  • MR urography is an alternative if CT is contraindicated 4
  • Renal ultrasound with retrograde pyelography can be considered if CT and MR are not feasible 4
• For children or low-risk patients with microscopic hematuria:
  • Renal and bladder ultrasound is the appropriate first-line imaging test 1

Cystoscopy Recommendations

• Cystoscopy is indicated for:
  • All patients with gross hematuria 1, 4
  • Patients ≥40 years with microscopic hematuria 1
  • Patients <40 years with risk factors for bladder cancer 1
• Flexible cystoscopy is preferred over rigid cystoscopy due to less pain, fewer post-procedure symptoms, and at least equivalent diagnostic accuracy 1

Specialist Referral

• Urologic referral is necessary for:
  • All patients with gross hematuria 4, 3
  • Patients with microscopic hematuria and risk factors for malignancy 3
  • Patients with persistent unexplained hematuria 1
• Nephrology referral is recommended if there is evidence of glomerular disease 3

Follow-up Recommendations

• For patients with a negative initial evaluation of asymptomatic microscopic hematuria:
  • Repeat urinalysis, urine cytology, and blood pressure determination at 6,12,24, and 36 months 1, 5
  • Additional evaluation including repeat imaging and cystoscopy may be warranted in patients with persistent hematuria 1
  • Immediate urologic reevaluation is necessary if any of the following occur: gross hematuria, abnormal urinary cytology, or irritative voiding symptoms in the absence of infection 1
  • Consider nephrology referral if hematuria persists with development of hypertension, proteinuria, or evidence of glomerular bleeding 1

Common Pitfalls to Avoid

• Do not attribute hematuria solely to antiplatelet or anticoagulant medications without further investigation 4, 5
• Do not assume BPH or hypertension is the cause of hematuria without proper evaluation 5
• Do not delay urologic referral for patients with gross hematuria while waiting for other test results 4
• Do not rely solely on dipstick results without microscopic confirmation 1